Drug-resistant super-bugsProtein study to help in superbug battle

Published 1 February 2012

Scientists have shed light on the way superbugs such as MRSA are able to become resistant to antibiotics; the researchers have done it by mapping the complex molecular structure of an enzyme found in many bacteria

Scientists have shed light on the way superbugs such as MRSA are able to become resistant to antibiotics. The researchers have done it by mapping the complex molecular structure of an enzyme found in many bacteria.

These molecules — known as restriction enzymes — control the speed at which bacteria can acquire resistance to drugs and eventually become superbugs.

A University of Edinburgh release reports that the study, carried out by an international team including scientists from the University of Edinburgh, focused on E. coli. The results, however, would apply to many other infectious bacteria.

After prolonged treatment with antibiotics, bacteria may evolve to become resistant to many drugs, as is the case with superbugs such as MRSA. Bacteria become resistant by absorbing DNA — usually from other bugs or viruses — which contains genetic information enabling the bacteria to block the action of drugs.

Enzymes that work in this way are believed to have evolved as a defense mechanism for bacteria.

The researchers also studied the enzyme in action by reacting it with DNA from another organism. They were able to model the mechanism by which the enzyme disables foreign DNA, while safeguarding the bacteria’s own genetic material.

Restriction enzymes’ ability to sever genetic material is widely applied by scientists to cut and paste strands of DNA in genetic engineering.

The release notes that the study was carried out in collaboration with the Universities of Leeds and Portsmouth with partners in Poland and France. It was supported by the Biotechnology and Biological Sciences Research Council and the Wellcome Trust and published in Genes and Development journal.

“We have known for some time that these enzymes are very effective in protecting bacteria from attack by other species. Now we have painted a picture of how this occurs, which should prove to be a valuable insight in tackling the spread of antibiotic-resistant superbugs,” said Dr. David Dryden of the university’s School of Chemistry.